Revert "drm/i915: Use PM QoS to prevent C-State starvation of gen3 GPU"

Using PM latency request turns out to be very fragile and only works for
some systems, depending upon the ACPI implementation. However, I've
stumbled across a promising bit in INSTPM: "Interrupt-Based AGPBUSY#".

This reverts commit b0b544cd37c060e261afb2cf486296983fcb56da.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3d4fd01..7a4725c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -35,7 +35,6 @@
 #include "intel_ringbuffer.h"
 #include <linux/io-mapping.h>
 #include <linux/i2c.h>
-#include <linux/pm_qos_params.h>
 #include <drm/intel-gtt.h>
 
 /* General customization:
@@ -309,10 +308,6 @@ typedef struct drm_i915_private {
        int vblank_pipe;
        int num_pipe;
 
-       atomic_t vblank_enabled;
-       struct pm_qos_request_list vblank_pm_qos;
-       struct work_struct vblank_work;
-
        /* For hangcheck timer */
 #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
        struct timer_list hangcheck_timer;

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 7f1362d..39d7cd3 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1332,22 +1332,6 @@ int i915_irq_wait(struct drm_device *dev, void *data,
        return i915_wait_irq(dev, irqwait->irq_seq);
 }
 
-static void i915_vblank_work_func(struct work_struct *work)
-{
-       drm_i915_private_t *dev_priv =
-               container_of(work, drm_i915_private_t, vblank_work);
-
-       if (atomic_read(&dev_priv->vblank_enabled)) {
-               if (!dev_priv->vblank_pm_qos.pm_qos_class)
-                       pm_qos_add_request(&dev_priv->vblank_pm_qos,
-                                          PM_QOS_CPU_DMA_LATENCY,
-                                          15); //>=20 won't work
-       } else {
-               if (dev_priv->vblank_pm_qos.pm_qos_class)
-                       pm_qos_remove_request(&dev_priv->vblank_pm_qos);
-       }
-}
-
 /* Called from drm generic code, passed 'crtc' which
  * we use as a pipe index
  */
@@ -1370,16 +1354,6 @@ int i915_enable_vblank(struct drm_device *dev, int pipe)
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_VBLANK_INTERRUPT_ENABLE);
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
-
-       /* gen3 platforms have an issue with vsync interrupts not reaching
-        * cpu during deep c-state sleep (>C1), so we need to install a
-        * PM QoS handle to prevent C-state starvation of the GPU.
-        */
-       if (dev_priv->info->gen == 3 && !dev_priv->info->is_g33) {
-               atomic_inc(&dev_priv->vblank_enabled);
-               queue_work(dev_priv->wq, &dev_priv->vblank_work);
-       }
-
        return 0;
 }
 
@@ -1391,11 +1365,6 @@ void i915_disable_vblank(struct drm_device *dev, int pipe)
        drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
        unsigned long irqflags;
 
-       if (dev_priv->info->gen == 3 && !dev_priv->info->is_g33) {
-               atomic_dec(&dev_priv->vblank_enabled);
-               queue_work(dev_priv->wq, &dev_priv->vblank_work);
-       }
-
        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
        if (HAS_PCH_SPLIT(dev))
                ironlake_disable_display_irq(dev_priv, (pipe == 0) ?
@@ -1678,11 +1647,9 @@ void i915_driver_irq_preinstall(struct drm_device * dev)
        int pipe;
 
        atomic_set(&dev_priv->irq_received, 0);
-       atomic_set(&dev_priv->vblank_enabled, 0);
 
        INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
        INIT_WORK(&dev_priv->error_work, i915_error_work_func);
-       INIT_WORK(&dev_priv->vblank_work, i915_vblank_work_func);
 
        if (HAS_PCH_SPLIT(dev)) {
                ironlake_irq_preinstall(dev);